Reinforced concrete reinforcement for highly stressed structural components



March 26, 1968 HEIWOLT ET AL 3,374,595

REINFORCED CONCRETE REINFORCEMENT FOR HIGHLY STRESSED STRUCTURAL COMPONENTS Filed D80. 14, 1965 HG. 2c

g #7630 F/6I3; F76. I

F76 4b F/G. 4c:

lNVENTQRS GBrLar'd H houlw 1/0 4 I United States Patent 3,374,595 REINFORCED CONCRETE REINFORCEMENT FOR HIGHLY STRESSED STRUCTURAL COMPONENTS Gerhard Heiwolt, Braunschweig, and Guenter Voss, Wolfenbuttel, Germany, assignors to Salzgitter Industriebau Gesellschaft m.b.H., Salzgitter-Drutte, Germany Filed Dec. 14, 1965, Ser. No. 513,778 Claims priority, application Germany, Dec. 18, 1964, S 94,695 8 Claims. (Cl. 52648) ABSTRACT OF THE DISCLOSURE A reinforcement arrangement for concrete bodies, particularly for tunnel arches and the like, comprising in combination, a plurality of longitudinally arrayed outer arched unitary reinforcing elements each provided with inwardly projecting elongated pegs, a plurality of longitudinally arrayed inner arched unitary reinforcing elements each received with spacing within the confines of one of the outer elements and having outwardly projecting elongated pegs, and reinforcing filler means interposed between respective sets composed of an inner and an outer arched element, the pegs meshing with the filler means whereby, when the arrangement is embedded in a body of hardened concrete the pegs interconnect the elements of the sets and the filler means in shear-resistant relationship.

The present invention concerns a reinforced concrete reinforcement for highly stressed structural components, such as tunnel arches, with the reinforcement steel rods arranged in layers.

Conventional reinforcement in tunnel construction comprise an outer and an inner layer of round steel rod reinforcement. The two layers are interconnected by means of a yoke reinforcement to receive shearing forces. The yokes span the two reinforcement layers. The two reinforcement layers are each joined into a net by means of distribution irons.

In highly stressed tunnel arches inserting the conventional round steel reinforcement hitherto involved considerable effort, since the transverse, longitudinal and distribution reinforcements had to be interlaced. It was necessary to thread all the remainder of reinforcement components into the endless yokes of the shearing reinforcement. With the restricted space conditions in tunnel construction this is difiicult, more especially in the region of the spherical cap of the tunnel, if the arch is to be closed at this point. In this case the use of endless yokes was impossible in most cases.

Since highly stressed tunnel arches in most cases required a shearing reinforcement and moreover very large steel cross-sections for the inner and outer layers of reinforcement, it was not possible to use prefabricated reinforcement mats each having a large area.

The object of the present invention is to eliminate the aforementioned deficiencies. According to the present invention the individual layers comprise juxtaposed prefabricated steel elements having pegs secured thereon at an angle, which are also inserted through meshes of structural steel mats also prefabricated and laid longitudinally of the steel elements, and furthermore the layers, after the concrete has set, are interconnected so as to be shear resistant. Conveniently in this case the prefabricated steel elements are in the form of fiat steel bars. This ensures that all elements of the united reinforcement are adapted to be inserted successively in the form of prefabricated structural components without having to hange over repeatedly the reinforecment components already installed during the completion of the united rein-forecrnent, as has been necessary when using known reinforcement. Furthermore this provides the advantage that for strong reinforcement prefabricated reinforcement mats of large area may be used, since the steel strips which are used in consideration of the anti-shear anchor welded thereon may be added to the necessary proportion of reinforcement of the mats.

In a further embodiment of the invention the shear resistant connection of the layers is obtained by the fact that the pegs of the opposing layers project towards, so as to overlap, one another. This is particularly simple form of shear resistant connection.

In an alternative embodiment of the invention the shear resistant connection between the layers in set concrete is constituted by prefabricated bent steel reinforcements. It is thus possible to use reinforcement rods assembled into a basket-like configuration or reinforcement rods or even strip-like curved reinforcement rods can be used.

The reinforcements in accordance with the invention may be shaped to accommodate all irregular surfaces in the tunnel or any other structural site, resulting from the excavation of the tunnel or the temporary tunnel lining inserted.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a vertical section partly in elevation showing a preferred form of reinforcement in accordance with the invention for incorporation within the concrete lining of a tunnel roof;

FIG. 2a is a composite view, the upper part of which is a sectional elevation and the lower part of which is a plan of a detail, showing one suitable type of yoke basket which may be used in the embodiment of FIG. 1

FIGS. 2b and 2c are both composite views, similar to FIG. 2a showing alternative yoke basket structures;

FIGS. 3a, 3b, 3c and 3d are respectively fragmentary views of details in vertical section showing alternative antishear peg constructions; and

FIGS. 4a, 4b, 4c and 4a are respectively fragmentary vertical sectional elevations showing alternative overlapping arrangements of the anti-shear pegs in the shear resistant connections between two layers of reinforcement in accordance with the invention.

The reinforcement illustrated in FIG. 1 comprises steel strips 1 with anti-shear pegs 2 welded thereon. These steel strips are first applied against the excavated inner tunnel surface as external ring of reinforcement. Then the prefalbricated reinforcement mats of the external reinforcement 3 are so placed on the steel strip that the anti-shear pegs of the steel strips project through the meshes of the mats.

The anti-shear pegs welded in position to increase the tear-out strength may be provided with an additional reinforcement coil 8. The prefabricated yoke baskets 4 are inserted over the row of anti-shear pegs 2 of the steel strips 1 so that the anti-shear pegs extend into the yoke baskets. Prefabricated reinforcement mats 5 are placed over the completely assembled and installed yoke baskets 4. To complete the assembly steel strips 6 with anti-shear pegs 7 3 welded thereon in the same way as the steel strips 1 are placed over the reinforcement mats 5, so that the antishear pegs project through the mesh of the mats into the yoke baskets 4.

To assemble the structure illustrated in FIG. 1, the elements 1 are introduced into the tunnel or placed into whatever other position they are required to assume, whereupon the elements 3 are fastened to them. The yoke baskets 4 are now inserted with the reinforcements 9 located within the yoke baskets 4. Of course, the reinforcements 9 could be subsequently introduced also. The elements 5 are introduced next, it being assumed that this installation is being accomplished in a tunnel, and finally the elements 6 are positioned in their proper places. Thus, assembly of the construction in FIG. 1 presents no difiiculties as long as the necessary order of assembly is observed FIG. 2 illustrates various different embodiments of the yoke baskets shown in FIG. 1. Thus, FIG. 2a shows an arrangement in which the yoke baskets correspond to those shown in FIG. 1 and each consist of a reinforcing rodshaped element which is bent into rectangular or frameshaped form. Each such yoke basket 4 is then secured in the manner illusrtated to the strips 1 and 6. FIG. 2 shows the use of mounting reinforcements in form of substantially ring-shaped reinforcing rods 9 which are secured to the individual yoke baskets 4 in suitable manner.

FIG. 2b illustrates a modified embodiment wherein the yoke baskets are not comprised of a plurality of individual frame-shaped assemblies or sections, but where, as the lower portion of FIG. 2b shows, the yoke basket associated with each set of strips 1 and 6 is of one-piece construction and consists of a reinforcing rod or the like which is bent into a series of successive rectangular convolutions 10. In this embodiment the use of the mounting reinforcements 9 of FIG. 2a, which in the latter figure were necessary to secure the individual yoke baskets 4 together, is not required and consequently these mounting reinforcements 9 are omitted in FIG. 2b.

FIG. 20, finally, corresponds relatively closely to FIG. 21) except that the yoke basket here consists of a reinforcing rod bent into a plurality of successive convolutions 11 which, however, are of cylindrical or ring-shaped outline rather than of rectangular outline as is the case in FIG. 2b. In other respects the embodiment of FIG. 2c corresponds to that of FIG. 2b. A portion of the yoke basket consisting of the convolutions 11 is illustrated in the lower part of FIG. 20.

FIG. 3 shows in fragmentary views a plurality of different anti-shear peg embodiments. Specifically, FIG. 3a shows an anti-shear peg which corresponds to that illustrated in FIGS. 1 and 2. This, therefore, is not believed to require any detailed explanation. FIG. 3b, on the other hand, shows a construction in which the shear peg 2a is provided with a disc which constitutes the innermost head of the peg and which is adjustable in longitudinal direction of the latter, for instance by non-illustrated screw threads or the like. FIG. 30 differs from FIG. 3b in that the anti-shear peg 2b illustrated in FIG. 3 is provided with a hexagonal nut in place of the disc shown in FIG. 3b. The nut shown in FIG. 30 is also adjustable in longitudinal direction of the peg 2b as is suggested by the fact that, in the same manner as in FIG. 3b but unlike the illustration in FIG. 3a, a portion of the peg 2b is seen to he projecting downwardly beyond the nut. FIG. 3d, finally, shows the anti-shear peg 20 to be provided with a lower hooked end portion instead of the disc or nut illustrated in FIGS. 3a3c. With this embodiment the hooked end portion of the peg 20 can be hooked over a portion of the novel construction and this can then serve to etfect connection in the desired manner. It is also to be noted that in FIGS. 3a-3d the length of the anti-shear pegs is different, and this length can be varied at will and in accordance with the particular requirements of an individual application. We have 'found it advantageous if the length of the pegs provided on the elements 1 and 6, respectively, is such l that the inner ends of the respective pegs project past one another, that is overlap one another.

FIG. 4, finally, shows in several fragmentary vertical sectional elevations how the inner ends of the anti-shear pegs can be overlapped. FIG. 4a illustrates anti-shear pegs 2c and 70 corresponding to those shown in FIG. 3d. No specific explanation will be required because FIG. 4a is self-explanatory. This is also true of FIG. 4b where the shear pegs 2 and 7 will be seen to correspond to the ones illustrated in FIG. 2a. FIG. 4c shows a further possible embodiment of the anti-shear pegs, here illustrated with reference numeral 2d in the case of element 1 and 7d in the case of element 6. Again, the inner end portions of the anti-shear pegs are hook-shaped. However, the hooks are more open than those illustrated in FIG. 4a and they thus make it possible to push the ends of the respective pegs 2d and 7d over the customary reinforcing rods which are always embedded in reinforced concrete and which, because theydo not constitute a specific part of the present invention, are not separately identified with reference numerals. FIG. 4a, lastly, shows anti-shear pegs 2d and 7d, respectively, which correspond largely to those illustrated in FIG. 4c. FIG. 4d differs from FIG. 40, however, in that the pegs 2d and 7d are longer than those shown in FIG. 40 so that at least the peg 2d is hooked over the reinforcing rod located exteriorly of the mat 5, rather than interiorly as the case in FIG. 40.

We claim:

1. In a method of forming in situ a highly stressed concrete structure as a lining for a natural surface such as a tunnel wall, the steps of (a) placing against a natural surface a first series of prefabricated spaced mutually parallel steel strips each carrying at spaced intervals therealong a plurality of anti-shear pegs projecting away from said natural surface;

(b) placing a first steel mat in contact with said first series of strips and allowing the pegs to project through the interstices of the mat;

(c) placing a plurality of yoke cages in contact with said first steel mat so that at least one anti-shear peg projects into each cage; I

(d) placing a second mat in contact with said cages; and

(e) positioning inwardly of said first series of strips a second series of prefabricated spaced mutually parallel steel strips each carrying at spaced intervals therealong a plurality of additional anti-shear pegs and allowing said additional pegs to project towards said natural surface and into said cages through the interstices of 'said second mat.

2. A reinforcement arrangement for concrete bodies, particularly for tunnel arches and the like, comprising in combination, a plurality of longitudinally arrayed outer arched unitary reinforcing elements each provided with inwardly projecting elongated pegs; a plurality of longitudinally arrayed inner arched unitary reinforcing elements each received with spacing within the confines of one of said outer elements and having outwardly projecting elongated pegs; and reinforcing filler means interposed between respective sets composed of an inner and an outer arched element, said pegs meshing with said filler means whereby, when said arrangement is embedded in a body of hardened concrete, said pegs interconnect said elements of said sets and said filler means in shear-resistant relationship.

3. An arrangement as defined in claim 2, wherein said arched reinforcing elements are steel strips.

4. An arrangement as defined in claim 2, wherein the elements of each set are radially spaced from one another by a predetermined distance, and wherein at least some of the respective pegs have a length greater than half of said predetermined distance.

5. An arrangement as defined in claim 2, wherein said filler rneans comprises a plurality of assemblies at least one associated with each of said sets, and extending from one to the other of said elements of the associated set of elements.

6. An arrangement as defined in claim 5, wherein said assemblies are frame-shaped assemblies of reinforcing rods and wherein a plurality of such frame-shaped assemblies is associated with each of said sets and spaced from one another in circumferential direction of the elements of the respective set.

7. An arrangement as defined in claim 5, wherein said assemblies each consist of at least one convoluted reinforcing rod with the convolutions of each assembly extending between said elements of the respective set of elements.

8. An arrangement as defined in claim 5, wherein said filler means further comprises reinforcing mats interposed 1,171,379 2/1961 Germany.

779,478 7/ 1957 Great Britain. 865,535 4/1961 Great Britain. 945,258 12/ 1963 Great Britain.

BOBBY R. GAY, Primary Examiner.

DAVID J. WILLIAMOWSKY, Examiner.

R. D. KRAUS, Assistant Examiner. 

